A system comprising an electron beam column and an ion beam column having main axes extending under an angle relative to each other and intersecting a common work area can be used to process miniaturized objects. Herein, the electron beam column is operated as an electron microscope in order to obtain an image of a surface of the object to be processed. Locations which are to be processed on the surface of the object are determined based on the obtained image. The processing is then performed using an ion beam generated by the ion beam column. The ion beam may remove material from the surface of the object, wherein a suitable process gas may be supplied to the surface. The process gas is activated by the ion beam and causes an etching process. Such method is commonly referred to as ion beam milling or ion beam assisted etching. It is also possible to deposit material on the surface of the object using the ion beam. In such process, a suitable process gas is supplied to the surface of the object, and the ion beam activates the process gas to trigger a deposition process. Such method is commonly referred to as ion beam deposition.
An example of using such system for removal of material from a surface of an object is the manufacture of a section of a miniaturized device in order to assess a structure of the device or to determine an error in the structure of the device. In order to manufacture a sectional surface of the device, the ion beam is oriented nearly parallel to the manufactured sectional surface, and material is continuously removed from the sectional surface due to the action of the ion beam. The process of the removal of the material can be monitored using the electron microscope by orienting the sectional surface orthogonally to the main axis of the electron beam column and recording an electron microscopic image of the sectional surface. Based on the image it is possible to decide whether the material removal has reached a desired depth or whether additional material removal is required. If further material removal is required, the sample is again oriented such that the sectional surface is nearly parallel to the ion beam, and a further processing using the ion beam is performed.
Applying such method to larger objects allows to manufacture sectional surfaces having only a limited range of orientations relative to the object, relative to the ion beam column and relative to the electron beam column.
A further method in which the system illustrated above can be used is illustrated in the article “Geometric Compensation of Focused Ion Beam Machining Using Image Processing” von Hiwon Lee et al., Applied Physics Express 1 (2008). The method includes producing of a trench having a predetermined rectangular cross section in an object using an ion beam. In practice, the cross section of the manufactured trench will deviate from the desired cross section due to a re-deposition of sputtered material. The article illustrates the possibility of producing a cross section of a trench manufactured according to a first method and determining from such cross section those regions of the trench requiring a higher or a lower removal of material. Based on this information, the distribution of the ion beam intensity across the trench is corrected in a next corrected method. Such processing can be repeatedly performed in that a cross section is produced from a trench manufactured in a corrected method wherein a further correction for a further next corrected method is determined based on this cross section. If a method has been sufficiently corrected, it can be used to manufacture a plurality of trenches having a same geometry in a same object material.
Such processing is time consuming and does not always achieve the desired results.